PCI [not PCI-e] versus AGP cards

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TheSpook

Limp Gawd
Joined
Feb 12, 2004
Messages
379
Hey - I'm running a 9800Pro AGP with two 9250s [PCI]. Even with basic Direct X applications (plug-ins for Winamp, et cetera) the 9250s lag far more than I feel they should. Is this due to the bus limitations of PCI vs. AGP, or something else? Are newer PCI cards just optimized for 2d with 3d mostly ignored?

Thanks :).
 
There shouldn't be a difference between 3d and 2d performance, though, based on the PCI bus speed alone. Isn't the video card just pressing a pre-rendered bitmap to the monitor, whether or not it represents something 2d or 3d?
 
sorry to hijack this thread but I think my problem relates to this as well. I'm running a voodoo3 PCI card in my internet box (AMD 900mhz, 512mb of ram) and the 2d graphics are very slow. I'm pretty sure its the card rather than the computer but I cant be positive. For example, in Internet Explorer when I type an adress in, occasionaly the letters appear lagging behind my typing. Whats up with that? I'm running XP pro by the way.

Thanks
 
Foz2001 said:
sorry to hijack this thread but I think my problem relates to this as well. I'm running a voodoo3 PCI card in my internet box (AMD 900mhz, 512mb of ram) and the 2d graphics are very slow. I'm pretty sure its the card rather than the computer but I cant be positive. For example, in Internet Explorer when I type an adress in, occasionaly the letters appear lagging behind my typing. Whats up with that? I'm running XP pro by the way.

Thanks
Click to expand...

That's not your video card's fault.
 
TheSpook said:
There shouldn't be a difference between 3d and 2d performance, though, based on the PCI bus speed alone. Isn't the video card just pressing a pre-rendered bitmap to the monitor, whether or not it represents something 2d or 3d?
Click to expand...


Beeeeeeep! Wrong. A card rendering a 3D model with textures is ALOT more bandwith intestive then just displaying a 2d bitmap such as say, Duke Nukem. Someone who is more familiar with 3d modeling can tell you more, but its its a MAJOR difference and PCI's limited 133mpbs bandwith won't cut it for shoving high rez texture, shading, bump mapping, ect..ect..across to a video card to render
 
You're running TWO PCI cards? That's probably the issue. PCI splits its entire bandwidth across all the devices installed on the bus instead of giving each card its own bandwidth. So if you're running a pair of 9250's plus a sound card plus something else (I don't recall whether AGP takes any PCI bandwidth, but I don't think so, it's separate), you're stretching bandwidth too thin.

The shared bandwidth problem is one of the main reasons for PCI-Express. In PCIe each device gets its own separate data stream.
 
2D-based Windows APIs are still using the CPU entirely, so it's doubtful that's your problem. Even the fancy transparency effects some programs have are entirely done on the CPU. When Windows Vista rolls around, though... that'll be a different story.
 
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